Known systems of this general type comprise a dilatometer head having an expandable body defining an internal cavity, the dilatometer head being adapted to be lowered into a borehole formed for this purpose in materials which may be either natural (for example rocks, soil) or artificial (for example concrete, etc.) in conjunction with hydraulic pressure intensifying means for applying a radial force to the borehole wall through the agency of the expandable dilatometer head, and means for measuring and recording the resultant deformation as a function of the increased volume of the dilatometer head and the applied hydraulic pressure.
Typical pressure intensifiers for pressurizing the dilatometer head are manually-operated, and do not provide integrated pressure and volume measuring means capable of electrical communication with continuous storage or plotting devices. Their use is labour intensive, time consuming and subject to human error. Additionally, because of the rugged in-field use conditions and the high operating pressures normally encountered, it is a requirement that pressure intensifiers for this type of application be of strong, rigid construction. As a consequence, known forms of pressure intensifiers are generally large, heavy and cumbersome, particularly for in-field operations. Leakage has also been a common problem with known designs of intensifiers.
It is an object of the present invention to provide an improved pressure intensifier in which the above-mentioned limitations are overcome. This is achieved by providing a pressure intensifier which is highly portable while at the same time being of strong, rigid construction, and which is capable, in the preferred embodiment described, of producing pressures up to 124 MPa without significant leakage. Moreover, the intensifier of the invention may be used with a wide variety of hand operated or electrically operated hydraulic pumps, the latter of which can be connected to a servo-control unit for remote operation. Additionally, volume and pressure measuring means integrated into the intensifier allow for the continuous storage, plotting or printing of output data and for the simultaneous or subsequent processing of this data by appropriately programmed computer means. Thus, the pressure intensifier of the invention is particularly suited for integration into an automated, computerized dilatometer system for calculating the deformation modulus of rock or similar materials.